Coffee aging: When coffee tastes best

You may have noticed the roasting date on our coffee packaging, which we indicate next to the information about the origin and preparation of the coffee. There is a reason for this, because it lets you know exactly when your coffee was roasted. In this article, we will try to find out when coffee tastes best after roasting.

For many coffee drinkers and baristas, the thought "the fresher the better" often dominates – that would be the absolute credo when buying coffee. However, the taste profile of a freshly roasted coffee is completely different from a coffee that is perhaps 14 days old. And different is by no means bad! It is important to understand when the coffee has reached the perfect age after roasting, when all the flavours have matured perfectly. We also talk about "ageing" here.

First of all – what happens during roasting?

During roasting, a chain of physical and chemical reactions takes place. The so-called Maillard reaction plays a special role. Many things happen at the same time, for example, simple sugars split into multiple sugars, the residual moisture evaporates from the beans, the volume of the beans is increased and CO2 (carbon dioxide) is produced.

After the roasting process, the coffee starts to excrete CO2 and it is exposed to O2 (oxygen) at the same time. So our goal when storing in coffee packaging must be that the CO2 leaves the bag, but no additional oxygen enters. For this reason, semi-permeable valves are fitted to our coffee packaging.

The high CO2 content in the coffee after roasting can affect the brewing very strongly and make it much more difficult to achieve a good extraction. So it is very important that the coffee rests sufficiently after roasting to 'degas'. Degassing is essentially finding the moment when the coffee tastes best after roasting. This is almost comparable to opening a good red wine. When decanting, the wine must first "breathe" until it has developed its full potential.

Ideally, with coffee, we want to achieve a balance between the loss of flavours and the build-up of carbon dioxide. For most coffees, this process occurs in a window of 6 to 23 days after roasting. Coffee reaches its peak when CO2 levels begin to drop and the aroma is at its strongest. Exposure to O2 causes the coffee to age faster, losing flavour and aroma until it eventually tastes stale. When you open a really old pack of coffee and smell it, you notice it immediately.

Does roasted coffee have an expiry date?

In short - no. Coffee beans can theoretically be used months after roasting. However, the quality of the coffee's taste is limited in time and if you understand when your coffee tastes best, i.e. when it has reached its "peak of flavour", you can specifically train and improve your own sensory knowledge. Coffee is a natural product and like other natural products, its taste has an "expiry date".

When is coffee perfectly matured?

Ivo Weller, our roaster, knows that a large part of the characteristic properties of a coffee are influenced by factors such as cultivation, variety and preparation, and ultimately his work as a roaster.

If you have ever had the opportunity to smell green, i.e. unroasted coffee, you will probably have noticed a very grassy, straw-like aroma. This changes completely through the roasting process into aromas that are more reminiscent of popcorn or sweet malt. The change is so enormous that the actual aroma only really unfolds days after roasting.
As filter coffee, you can usually brew the beans after just a few days, but an espresso roast often needs a few weeks until it tastes perfect.

So if you want to know exactly how long you have to wait, the answer is simple: taste your coffee every day and compare the taste.

Do different processes age differently?

One of the difficult aspects of coffee is the different ageing rates between different preparation processes, as a look at the graph shows.

Washed coffees usually peak in flavour after six to 15 days, naturally prepared coffees take a few days longer and reach the sweet spot between ten and 20 days.

Then there are the funky wacky "carbonic maceration" coffees or "anaerobic fermentations".
Depending on the level of these experimental processing methods, these coffees behave much more complexly (like real divas) and need up to 23 days of degassing and resting.

How can I prevent my coffee from ageing further?

This has long been a problem for the specialty coffee industry. But there is a smart and sustainable way to preserve perfectly aged coffee: By freezing the aged coffee beans in vacuum-sealed bags or test tubes. This way we can effectively stop the ageing process - for up to two years! Find out more here.

written by

Nicole Battefeld

Nicole is Head Barista at Röststätte Berlin and German Barista Champion 2018. She has been part of the Röststätte team since 2014 and is now one of the absolute barista elite. In our blog, she talks about developments in the coffee world and leads training courses at the Röststätte Barista Academy.

Photos: Jordan Montgomery; Tai Lückerath; Laura Droße

website

www.roeststaette.com